Double-walled tumbler



FIG. 1 is a first embodiment of a double-walled tumbler showing my new design;

FIG. 2 is a front view thereof; the right side, left side and rear views are being identical;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a second embodiment of a double-walled tumbler;

FIG. 6 is a front view thereof; the right side, left side and rear views are being identical;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof. 

CLAIM The ornamental design for a double-walled tumbler, as shown and described. 